Research in the science of peak performance and motivation points to the fact that different tasks should ideally be matched to our energy level. For example, analytical tasks are best accomplished when our energy is high and we are free from distractions and able to focus. I generally wake up energized. Over the years, I have consistently stuck to the habit of eating my problems for breakfast. I'm someone who tends to overthink different scenarios and conversations that haven't happened yet. When I procrastinate on talking with an unhappy client or dealing with an unpleasant email, I find I waste too much emotional energy during the day. It's as if the task hangs over my head, and I'll spend more time worrying about it, talking about it, and avoiding it, than it would actually take to just take care of it. So for me, it'll always be the first thing I get done. If you know you are not a morning person, be strategic about scheduling your difficult work later in the day.

Countershading is the process of optical flattening that provides camouflage to animals. When sunlight illuminates an object from above, the object will be brightest on top. The color of the object will gradually shade darker toward the bottom. This shading gives the object depth and allows the viewer to distinguish its shape. Thus even if an animal is exactly, but uniformly, the same color as the substrate, it will be easily visible when illuminated. Most animals, however, are darker above than they are below. When they are illuminated from above, the darker back is lightened and the lighter belly is shaded. The animal thus appears to be a single color and easily blends in with the substrate. This pattern of coloration, or countershading, destroys the visual impression of shape in the organism. It allows the animal to blend in with its background.

Observational studies of humans cannot be properly controlled. Humans live different lifestyles and in different environments. Thus, they are insufficiently homogeneous to be suitable experimental subjects. These confounding factors undermine our ability to draw sound causal conclusions from human epidemiological surveys. Confounding factors are variables (known or unknown) that make it difficult for epidemiologists to isolate the effects of the specific variable being studied. For example, Taubes argued that since many people who drink also smoke, researchers have difficulty determining the link between alcohol consumption and cancer. Similarly, researchers in the famous Framingham study identified a significant correlation between coffee drinking and coronary heart disease. However, most of this correlation disappeared once researchers corrected for the fact that many coffee drinkers also smoke. If the confounding factors are known, it is often possible to correct for them. However, if they are unknown, they will undermine the reliability of the causal conclusions we draw from epidemiological surveys.

The right to be forgotten is a right distinct from but related to a right to privacy. The right to privacy is, among other things, the right for information traditionally regarded as protected or personal not to be revealed. The right to be forgotten, in contrast, can be applied to information that has been in the public domain. The right to be forgotten broadly includes the right of an individual not to be forever defined by information from a specific point in time. One motivation for such a right is to allow individuals to move on with their lives and not be defined by a specific event or period in their lives. For example, it has long been recognized in some countries, such as the UK and France, that even past criminal convictions should eventually be spent and not continue to affect a person's life. Despite the reason for supporting the right to be forgotten, the right to be forgotten can sometimes come into conflict with other rights. For example, formal exceptions are sometimes made for security or public health reasons.

To an economist who succeeds in figuring out a person's preference structure ― understanding whether the satisfaction gained from consuming one good is greater than that of another ― explaining behavior in terms of changes in underlying likes and dislikes is usually highly problematic. To argue, for instance, that the baby boom and then the baby bust resulted from an increase and then a decrease in the public's inherent taste for children, rather than a change in relative prices against a background of stable preferences, places a social scientist in an unsound position. In economics, such an argument about birth rates would be equivalent to saying that a rise and fall in mortality could be attributed to an increase in the inherent desire change for death. For an economist, changes in income and prices, rather than changes in tastes, affect birth rates. When income rises, for example, people want more children (or, as you will see later, more satisfaction derived from children), even if their inherent desire for children stays the same.

The difference in the Moon's gravitational pull on different parts of our planet effectively creates a stretching force. It makes our planet slightly stretched out along the line of sight to the Moon and slightly compressed along a line perpendicular to that. The tidal stretching caused by the Moon's gravity affects our entire planet, including both land and water, inside and out. However, the rigidity of rock means that land rises and falls with the tides by a much smaller amount than water, which is why we notice only the ocean tides. The stretching also explains why there are generally two high tides (and two low tides) in the ocean each day. Because Earth is stretched much like a rubber band, the oceans bulge out both on the side facing toward the Moon and on the side facing away from the Moon. As Earth rotates, we are carried through both of these tidal bulges each day, so we have high tide when we are in each of the two bulges and low tide at the midpoints in between.

A study investigated the economic cost of prejudice based on blind assumptions. Researchers gave a group of Danish teenagers the choice of working with one of two people. The teenager had never met either of them. One of the people had a name that suggested they were from a similar ethnic or religious background to the teenager. The other had a name that suggested they were from a different ethnic or religious background. The study showed that the teenagers were prepared to earn an average of 8% less if they could work with someone they thought came from the same ethnic or religious background. And this prejudice was evident among teenagers with ethnic majority names as well as those with ethnic minority names. The teenagers were blindly making assumptions about the race of their potential colleagues. They then applied prejudice to those assumptions, to the point where they actually allowed that prejudice to reduce their own potential income. The job required the two teenagers to work together for just 90 minutes. -> A study in which teenagers expressed a preference to work with someone of a similar background, even at a financial cost to themselves, suggests that an assumption-based prejudice can outweigh rational economic behavior.